DESCRIPTION (APPLICATION ABSTRACT): Both epidemiologic studies and randomized trials have shown that many surgical site infections (SSI) are preventable with appropriately timed antimicrobial prophylaxis. Patients receiving prophylaxis either well before or well after surgery are up to five times more likely to develop an SSI than those receiving appropriate therapy (Classen et al., 1992). Unfortunately, errors in antimicrobial prophylaxis timing are extremely common, with error rates typically reported to be between 35 and 40 percent. Given that errors in antimicrobial prophylaxis are so common and the consequences of error so grave, identifying methods to assist hospitals in improving prophylaxis must be a high priority. We propose to evaluate a multifaceted, theory-based intervention to assist hospitals in progressing through stages of organizational change to improve the prophylaxis process. We will test the impact of the intervention using a rigorous group-randomized, nested, pretest-posttest design (Murray, 1998). Our specific aims over the four-year project period are: 1) Determine the incidence of medication errors related to antimicrobial prophylaxis for cardiovascular surgery, joint replacement surgery, and hysterectomy in 40 hospitals recruited to participate in the study; 2) identify organizational and system factors associated with error rates; and 3) randomize the 40 hospitals to evaluate the effectiveness of a multifaceted intervention. The intervention consists of a) the promotion of two specific process changes (the elimination of "on-call" ordering and the use of preprinted prophylaxis orders); b) a site visit; c) customized process feedback; d) facilitated benchmarking; and e) peer consultation. The 20 intervention hospitals will be compared with 20 hospitals that receive written feedback of their error rates only. The study has 80-percent power to detect a 12- to 15-percent improvement in the timing of prophylaxis in the full intervention group compared with the group that receives written feedback only. Data collection will be done at each participating hospital, and the medical records of 100 surgical patients before and after the intervention will be abstracted at each hospital to establish performance rates. Changes in the processes of care and the evolution through stages of organizational change will also be assessed. This application represents the combined efforts of three organizations devoted to improving patient care through error reduction: the Society for Healthcare Epidemiology of America, the Joint Commission on Accreditation of Healthcare Organizations, and the Centers for Disease Control and Prevention. Health Care Quality & Effectiveness Research SS KRITCHEVSKY, STEPHEN B. Each organization is providing unique abilities and expertise to address the important issue of antimicrobial prophylaxis errors.